1. Field of the Invention
The present invention relates to an image switching display device, and more particularly to a 2D/3D image switching display device capable of switching a 2D or 3D image display status.
2. Description of the Related Art
The principle of present well-known stereo image display technologies adopts a binocular disparity for receiving different images from both left and right eyes of a user respectively, and finally the user's brain merges the images into a stereo image. In naked-eye stereo display technologies, there are two main types of structures, respectively: lenticular lens and barrier, and these structures have advantages and disadvantages, wherein the lenticular lens includes a plurality of slender straight convex lenses arranged continuously along an axial direction to produce different views to the left and right eyes by the principle of optical refraction. Compared with the barrier, the lenticular lens makes use of the light refraction to achieve the light division effect, so that there will be less loss of light and better brightness, but the refraction occurred at edges of the lens is restricted and the refraction effect is poor, or stray light is produced due to factors such as the manufacturing discrepancy of the lenticular lens and the difficulty of leveling a lens surface, and thus blurring a portion of a stereo image and affecting the overall display effect of the 3D image. In addition, the barrier uses a whole row of obstacles to limit the emission of lights at a certain angle and allows viewing images of a certain angle to be transmitted to the left and right eyes to produce a stereo image. Compared with the lenticular lens, the single lens image is clearer, but the congenital structural characteristic will results in drawbacks such as reducing the overall brightness and the resolution of the image, etc.
In addition, the general stereo display device can display stereo images only, but cannot switch between planar images and stereo images, and the main reason resides on that after the lenticular lens or barrier is combined with the general display device, and all planar images passed through lenticular lens or barrier are distinguished as left eye images and right eye images, unless a stereo image display module is installed externally. If it is not necessary to display stereo images, the external stereo image display module is removed from the display device. However, the aforementioned application requires a precious alignment to avoid a reduced image resolution or a deviation. Therefore, manufacturers have developed a stereo image display device capable of switching the display between stereo images and planar images.
As disclosed in R.O.C. Pat. No. M371902 entitled “Display device for switching 2D planar image/3D stereo image display screen, the display device comprises a flat display device and a parallax barrier panel installed on a display surface of the flat display device, and the parallax barrier panel includes a grid pattern having a first electrochromic material layer and a second electrochromic material layer, wherein the grid pattern, the first electrochromic material layer and the second electrochromic material layer are transparent in a 2D planar image display mode, and the grid pattern is an opaque pattern, and the first electrochromic material layer has a first color, and the second electrochromic material layer has a second color in a 3D stereo image display mode.
As disclosed in R.O.C. Pat. No. M368088 entitled “Display device for switching 2D planar image/3D stereo image display screen”, the display device comprises: a first substrate; a parallax barrier unit installed under the first substrate; a color filter unit installed under the parallax barrier unit; a common electrode installed under the color filter unit; a liquid crystal unit installed under the common electrode; a plurality of thin film transistors installed under the liquid crystal unit; a second substrate installed under the plurality of thin film transistors; and a light source installed under the second substrate, such that the parallax barrier unit is provided for modulating a planar image and a stereo image, reducing the thickness of the conventional display device, and lowering the assembling cost.
The foregoing two patented technologies use an electrochromic material as a parallax barrier device for displaying a stereo image, but both structures have a common drawback of missing a necessary electrolytic layer of the electrochromic device which can supply ions to an electrolytic layer of the electrochromic layer, no that the electrochromic device cannot produce a reversible reaction of oxidation or reduction to complete a coloring or discoloring change, and the foregoing two patented technologies are not feasible. In addition, both transparent electrode layer and electrochromic material layer of the parallax barrier device come with a grid pattern and require a complicated manufacturing processes including layer coating, sputtering or etching to achieve the precise alignment of each layer. Furthermore, all layers include a grid pattern, and thus a hollow area is formed between the grids, and the hollow area will affect the overall penetration, refraction or reflection of the light. Even for a general 2D display, the image quality of the display device may be affected, and the chromic aberration or the brightness uniformity may be resulted. In R.O.C. Pat. No. N4368088, another structure for implanting a substrate of the liquid display device is implanted into an insulating transparent material by the grid pattern, and thus the thickness of the stereo image liquid display device can be reduced, but the manufacturing process will be very complicated.
Although the foregoing patented technologies can switch the planar and stereo display, yet these technologies cannot change the angle of the stereo display for a handheld device that provides a flexible viewing angle, and thus users have to view the 3D image from a specific direction.